Popularization of 3D television (3DTV) activates not only supply of 3D video content according to storage media but also transmission of 3D video content according to digital broadcast.
In general, a 3D image provides user's eyes with a stereoscopic effect using the stereoscopic visual principle of the eyes. A human being feels perspective through a binocular parallax caused by a distance between his or her eyes spaced apart from each other by about 65 mm, such that the 3D image enables both right and left eyes to respectively view associated planar images, resulting in the stereoscopic effect and the perspective effect.
The above-mentioned 3D image display method may be classified into a stereoscopic scheme, a volumetric scheme, a holographic scheme, etc. In case of using the stereoscopic scheme, the 3D image display method provides a left view image to be viewed by the left eye and a right view image to be viewed by the right eye, such that the user's left eye views the left view image and the user's right eye views the right view image through either polarization glasses or a display device, resulting in recognition of the 3D image effect.
To provide a 3D broadcast service, it is necessary to respectively transmit the left view image and the right view image and appropriately process the left view image and the right view image by a broadcast receiver to generate a 3D image. Accordingly, additional signaling information for 3D broadcast signal processing is needed.
A 3D broadcast signal is generated in a broadcasting station and transmitted therefrom. An on-screen display (OSD) used in the broadcast receiver is generated by the broadcast receiver and does not take into account the 3D broadcast service. When an OSD of the broadcast receiver is displayed while 3D broadcast content is displayed, a user may be hindered from viewing the 3D broadcast content since display of the OSD does not take into account depth information of the 3D broadcast content.
Furthermore, an overlay embedded in 3D broadcast content may be displayed having a depth different from that of the 3D broadcast content. In this case, it is necessary to take into account the depths of the embedded overlay and 3D broadcast content when the broadcast receiver displays the OSD (embedded overlay).